Airplane construction



Oct. 11, 1938.

W. B. FIRN ER AIRPLANE CONSTRUCTION.

Original Filed Sept. 17, 1935 4 Sheets-Sheet l INVENTOR.

Y ATToRN Ys.

' Oct. 11, 1938.

4 Sheets-Sheet 2 Original Filed Sept. 17, 1955 INVEQLTQR.

ATTORNEYS.

CCL l1, 1938, w. B. FIRNER AIRPLANE coNsTRUcTIoN original Filed sept. 1v, 1955 4 Sheets-Sheet 5 W. B. FIRNER Oct. 1l, 1938.

AIRPLANE CONSTRUCTION Original Filed Sept'.

17, 1935 4 Sheets-Sheet 4 y BY GMW-M ATTORNEYS.

Patented' Oct. 11, 1938 l V l 2,132,529

UNITEDl STATES. PATENT OFFICE AIRPLANE CONSTRUCTION William B. Firner, Detroit, Mich.

Continuation of application Serial No. 561,219,

September 4, 1931. This application September 17, 1935, Serial No. 40,991. Renewed October 19, 1936 19 Claims. (Cl. 244-119) This invention relates to aircraft and more below the body or shell of the ship, such substruc' particularly to the fabrication of the fuselage ture providing a means for attachment of a Wing, thereof, an object of the invention being to proenabling the wing to be positioned a greater disvide an airplane fuselage construction adapted tance below the neutral axis of the body, heneeto be utilized with varioustypes of aircraft and producing in operation a greater ground pack, 5

embodying certain improvements and novel feaslower landing Speed and quicker takeeff. tures of construction whereby substantial savings Other objects of this invention will appear in in the cost of manufacture are obtained while at the following description and appended claims, the same time permitting maximum efficiency in reference being had to the accompanying drawoperation, high strength-weight ratio and lfull ings forming a part of this speeiCatiOn wherein 10 latitude to effect the desired stream lining to relike reference characters designate corresponding duce air resistance during flight. parts in the Several VieWS.

The present application is a continuation of Fig. 1 is a Side elevatiOn, partly diagrammatic. my co-pending application Serial No. 561,219, filed illustrating one embo-diment of the invention. September 4, 1931. Fig. 2 is a perspective view of a fuselage conl5 A further object of the invention. is to provide struction embodying theinvention. parts being an improved airplane fuselage construction havlemOVed fOr the DurDOSe 0f Clearness. ing a novel framework so designed as to provide Flg- 3 iS a plan VieW, Partly diagrammatic. 0f suitable passenger andcargo space, and fabri the COHStruCtiOn ShOWn in Fig- 1.

vzo cated so as to take substantially au initiai Fg- 4is afrcnt elevation. partly diagrammatic. 20

stresses and to carry all the load without any subillustrating the fuselage.

stantial stress or torque being transmitted Fig. 5 is a fragmentary detail View ShOWirlg the through the she11 or skin carried by the frameconnecting means for the shell members. work. Fig. 6 is a fragmentary detail view showing the A further object of the invention is to proauxiliary landing skid- 25 vide an improved airplane fuselage having a sup- Fig. 7 iS a detail VieW 0f the rudder mounting porting frame constructed to form a bulkhead With a DOrtiOn thereof enlarged in Section. amidship, which bulkhead provides a focal point Fig 8 is a Plan VieW Of the Construction Shown for all forces and stresses to which the craft is in Flg 7 subjected during operation. Moreover, the im- Fig. 9 iS a fragmentary DerSDeCtiVe VieW 0f a 30 proved construction 0f the frame is such as to modified form of skeleton frame for the fuselage. provide a reinforcing enclosure for a passenger or Fig- 10 iS a front eleVatiOh. Partly diagramoperators compartment in advance of the bulkmatie. 0f the fuselagehead. In addition the construction 'of the frame Il? is t0 be understood that the DhraSeOlOgy 0r is such as to provide a stronger and more cicient terminology employed herein is fOr the Purpose 35 means for attachment of. the Wings of the Craft, of description and not of limitation, and it is not either in the monoplane or biplane type of airintended to limit the invention claimed herein beplane. yond the requirements of the prior art.

A further feature of the invention resides in Referringto the drawinesand more particularly 40 the fact that the frame is constructed so as to Flg' 2l the fuselage 0f the allplane Shown by Way 40 provide a safety landing skid extending longitu- 0f example in the present lnStanCe comprises a dinally between the wheels of the landing gear. main frame for Supporting the engine the eln- A further object of the invention is to pro- Denhage. the Shell and Other Darts 0f the Craft. vide an improved fuselage which Combines any this frame being preferably constructed of strucadvantages of the monocoque and steel tube types tural members formed 0f relatively light metal. 45

of fuselage while eliminating many of the disad- Such as aluminum alloy 0r Other equivalent metal. vantages thereof particularly the cost of fabrica- Adlaeent the DaSSenger 0r Operators Comparttion. By virtue of the invention the framework ment B there is prOVded a frame A WhiCh in the of the fuselage may be formed of structural alu- Present instance comprises a Structural I-bar minum or an equivalent metal, and may be fabribent preferably into substantially oblong shape to 50 cated more cheaply and easily than present types provide upper and lOWer vertically spaced l0ngi'- of fuselages. tudinal sides 9 and l0 respectively, joined in rear A further feature of the invention resides in of the compartment by a substantially vertical or the fact that the framework may be constructed upright side Il and in front thereof by a verto provide a substructure or sub-frame extending tical or upright side I2. For convenience in fab- 55 rication' the frame portion A in the present instance is shown as formed from a single structural bar with the ends overlapped and riveted together through connecting plates I3 which in turn provide means for attaching a wing. This frame A, however, may be formed of several connected members, as desired, and it will also be understood that in the case of larger types-of airplanes, especially of the multi-motor kind, a plurality of frame portions A, laterally spaced, may be utilized, and in such case each of such frames may, if desired, be constructed to support an engine.

'I'he frame A is preferably reinforced in rear of the compartment B so as to provide a bulkhead into which the stresses and strains are transmitted. A vertical I-bar i4 bisects this frame and is riveted at opposite ends to the sides 9 and lil. Riveted at opposite sides of the member i4 and extending rearwardly in diverging relation are pairs of bars I5 and i8 which are riveted at their outer ends to the frame A. An I-bar i1 connects the portion i2 of frame A to the lower end of the pillar i4, extending longitudinally beneath the iioor of the compartment. Extending laterally from the lower part of the pillar I4 are a pair of I-bars I3 and i 9 which are secured to I the member i4 by means of angle plates and are braced by means of bars 28 and 2|. A pair of I- bars 22 and 23 are secured through the medium of angles plates to the lower part of the front portion i2 of the frame A, and these in like manner are braced by means of bars 24 and 25. A channel member 28 connects the member 22 to the member I8, and a similar channel 21 connects the member 23 with the member i9, these channel members together with the truss member i1 providingthe supporting means for the floor of the compartment.

in the present instance the tail assembly or empennage is supported from the frame A by means of a cantilever beam or truss extending from the bulkhead axially and rearwardly through the tail. This truss in the present instance comprises two channel members 28 and 29 extending at opposite sides of the frame portion il and riveted thereto, and also riveted at their forward ends to opposite sides of the pillar i4. At their rear ends the channel members 28 and 29 are connected together by means of a vertical I-bar 38 which in turn supports the tail skid or wheel.

Within the compartment B a seat for the operator and passengers, depending upon the capacity of the craft, may be provided by means of transverse channel members 3i and 32 secured to the floor supports I1, 26, and 21, and connected together by means of end bars 33 and 34.

The present invention also contemplates the provision of novel and improved means for covering the frame of the craft so as to produce a shell of relatively inexpensive construction, easily installed and arranged to permit ready access to the interior of the airplane, such as for inspection purposes. Furthermore, the construction of the shell is such as to facilitate designing of the plane to produce the desired stream lining.

Mounted at intervals along the tail boom 28, 29, are a plurality of shell supporting rings or hoops 35 and 88, which may be formed of metal or other suitable material. The hoop '35 is braced in position by means of struts 35a secured to and projecting outwardly from the members 28 and 29. In like manner the hoop or ring 38 is supported in position by means of similar struts 36a.

aisance Additional hoop or ring members 31, 33, 33, and 48 are mounted at intervals along the fuselage and are provided for the purpose of supporting other portions of the shell. The ring or hoop 31 is braced by 'means of struts or spreader bars 31a. The hoops or rings 38 and 39 extend beneathv the floor supporting structural members and are held in proper positions by means of the several frame bars 4i carried by the frame 9. these frame bars providing a supporting means for the wind shield. As will be seen in Fig. 2 the ring or hoop 48 at the forward end of the fuselage is braced in position by means of the frame members 22 and 23, the upper ends of the hoop being fastened to the vertical frame portion I2.

In the present instance the shell or so-called "skin .comprises a series of sheet metal panels. preferably formed of light aluminum alloy or similar material. 'I'hese panels comprise hinged pairs, each pair being permanently stamped to provide the desired configuration so'that when assembled the proper shape will be given to the shell of the craft, particularly for stream lining purposes. As illustrated in the present case, by way of example, a pair of similarly shaped panels 42 and 42a are supported on the hoop or ring 33; a pair of panels 43 and 43a are carried by the spaced hoops or rings 3l and 38; a pair of similar panels 44 are in like manner stamped so as to rit over the rings or hoops 38 and 31. Additional pairs of panels 43 and 41 are mounted on the hoops or rings 33, 38 and 48, all of these panels being stamped so as to conform to the predetermined shape or curvature of the various hoop or ring members. The several pairs of panels are preferably hinged together along the bottom of the shell, and this is preferably accomplished by forming adjacent edges of the respective panels with interlocking knuckle portions which are joined together by means of longitudinally extending pintle pins. thus producing a piano hinge and providing a very strong connection. Consewith notched portions iiwithin which are con-l fined the members of a conventional turn buckle 52 secured to the panels 42 and 42a. By tightening the turn buckle these panels may be drawn firmly into position on the supporting hoop or ring 35. In like manner the remaining pairs of panels forming the shell may be connected tcgether and clamped in positions on their ring or hoop supports. The longitudinal joint between the pairs of panel members at the upper part of the shell may be concealed by means of a iinishing strip 53. As indicated in Fig. l, a suitable fairing 54 may be provided for the purpose of covering the upper stretch 9 of the frame A.

The invention may be applied'either to the monoplane or biplane type of craft, the latter being shown in the present instance for the purpose of illustration. Accordingly the upper wing sections 55 may be mounted on the upper portion 9 of the frame A through the medium of hinge connections 55, and the lower wing 31 mounted on the bottom ill of the frame A through the medium of hinge connections Il. It 1g will thus be seen from the foregoing that the lower wing extends on a. plane below the body or shell of the craft, this being possible by extending the side I of the oblong frame below the major area of the craft to provide a substructure.

Thus, from the foregoing, it will be seen that the low wing is fastened to a sub-frame extending below the fuselage or body of the craft. This enables the wing to be positioned nearer the ground to produce a more eilicient ground pack without, however, producing any ground interference with the fuselage. Consequently, a lower landing speed and a. quicker take-off is possible.

' Moreover, this construction provides a more desirable gap chord ratio, providing a high positive stagger for visibility'purposes and substantially equal loading of both wings in the case of a biplane. Also, the arrangement of the upper wing in connection with the upper part of the frame A places the bottom of the upper wing on a horizontal line with respect to tho line of vision which gives the inexperienced flyer an immediate sense of balance when in the air.

The usual landing gear, the wheels thereof being indicated at 58, is carried by the subframe structure I0, and the latter is so arranged that it may be utilized to provide an auxiliary landing skid intermediate the wheels of the landing gear, as illustrated particularly in Figs. 1 and 4. In the present instance the landing skid comprises a curved structural T-bar 59, secured at its forward end to the frame member lll, the forward and upward curve of the bar 59 being continuedinto the forward curved portion of frame member I0. This skid member is rigidly braced by means of struts '6I secured to the frame Ill, and its rear end is connected thereto by means of a structural bar 60. From the foregoing it will readily be seen that in case the landing gear fails or a nose-over occurs upon failure of the landing gear, the portions l0 and 59 will act as a skid thus minimizing the danger of damage. The sub-structure I0 and 59 extending below the body of' the craft-centrally thereof is covered by a suitable fairing, thus forming in appearance a single longitudinal fin which will function as a stabilizer during ight.

The empennage indicated in general at C, is carried by the rear ends of the truss or tail boom 28, 29. The usual tail wheel or shoe 63 is carried by a cantilever spring 62 which is attached to the strut 30 and to the bar 28 by means of a shackle 63a. In accordance with the present invention the stabilizer n 64 and also the 'rudder 66 may be mounted so as to extend below the rear end of the fuselage. This construction lowers the center of pressure on the rudder and cuts down the torque through the fuselage affording a greater degree of lateral stability.

The rudder mounting comprises a vertical T- bar 65 fastened to a ller block 61 fastened between the ends of the truss members 28 and 29.

,Secured to the upper and lower ends of the bar 65 are brackets 68 having sockets within which are pinned the opposite ends of a tube 69. The rudder 66 is carried by a sleeve 10 which is mounted to rotate on the tube 69 through the medium of suitable bushings 1I.

By extending the n and rudder belowv the fuselage greater directional stability is .afforded because the torque from the righting moment is reduced. It is well understood that during flight when a gust. of wind strikes the plane from the side the n area tends to cause the plane to nose into the wind. When the n area is wholly above the fuselage a rolling tendency is induced by the gust of wind striking the iin.

In accordance with the present invention, howaxis, and therefore the torque is reduced to a minimum., giving additional directional stability.

By placing a portion of the rudder below the fuselage the center of pressure is lowered so far that the torque action through the fuselage is almost negligible. This construction also equalizes the balance of vthe rudder along the rudder post and evenly distributes the strain on the hinge.

From the foregoing it will be seen that by Virtue of the present invention an airplane, either` of the monoplane or multiplane type having a single engine or a plurality of engines, may be constructed so as to embody any or all of a number of novel and advantageous features described herein. The framework of the fuselage, which sustains all stresses and strains, may be constructed of structural members of light aluminum alloy or equivalent metal, providing a high strength-weight ratio. This construction permits relatively cheap fabrication on a production basis with the elimination of considerable labor expense. It eliminates the slow and costly method of assembling and welding steel tubing, and eliminates the time and expense involved in present monocoque types of construction.

A combined nacelle and fuselage may be formed by fabricating a structural frame, or laterally spaced frames, preferably in the manner described so as to extend in a verticalplane or planes around the operators or passenger compartment. A bulkhead may be formed at the rear of such compartment for strength, and a tail supporting member attached to this frame. Forming rings or hoops for the covering or shell are mounted at suitable points along the frame, and the shell, preferably formed from stamped aluminum sheets or blanks, is held in place at one side by piano hinge members and at another side by tension applied through turnbuckles at the joints. The engine mount may be fastened to, and firmly supported, by the front portion of the frame. This frame also provides an improved means for` attaching and supporting a wing or wings and also the empennage or tail assembly.

It Will be seen that the improved construction eliminates the costly fabrication of bulkheads, the building of initial stresses into the skin, and the inefficient and expensive process of covering with cotton and then doping and painting. Moreover, the invention permits greater protection to operators or passengers, provides a greater safety factor in landing by virtue of the auxiliary or emergency landing skid, permits slower landing speed, quicker take-off, improved stabilization in flight, maximum streamlining possibilities in designing the craft, and full visibility during operation.

Referring to the embodiment of the invention illustrated in Figs. 9 and 10 there is here shown a skeleton frame A also preferably of relatively light metal, such as aluminum alloy, and also designed to embrace the space B for the passenger compartment. horizontal I-barsy 80 and 8| extending longitudinally and centrally of the compartment B' and This frame comprises spaced y 8Ia thereof, in rear of the passenger compartment, are bent downwardly in arcuate fashion to meet at a point 82 on the rearwardiy extending cantilever beams 83 where they are riveted to the latter. The bars and 8| extend forwardly in diverging relation and the forward ends are joined by a transverse tie bar 84. The frame at the lower side of the passenger compartment comprises an I-beam 85 extending centrally thereof, the rear end 85a of which being curved upwardly to contact the tail beam at point 82 where it is riveted to the latter.

The tail beam 83 hasa forward extension 83a, the terminal end of which is riveted to a vertical I-bar 86 centrally thereof, the latter bisecting the frame A'. The upper end of the pillar 86 is riveted to a cross tie 81 `of I-formation which joins the rear portions of the members 80 and 8l.

The lower end of the pillar 86 is riveted to the4 frame member 85 as indicated.

To the front terminal end of the beam 85 is riveted a transverse I-bar 88 extending at right angles thereto. Angular braces 89 connect the ends of this cross member to the beam 85. The forward terminal ends of the members 80 and 8l are joined to the center of the cross member B8 at 90a by angular I-bars 90 which together with member 84 form a triangular upright frame in advance of the passenger compartment. 'I'he outer ends of the front cross member 88 are braced and supported by means of angular brace members 9| riveted thereto and to the members 9D The front upright framing may be utilized as an engine mounting which may be connected thereto at suitable points indicated, for example, at 92. As in the previous embodiment the tail assembly or empennage is supported from the frame A' by means of the cantilever beam or truss 83 extending from the bulkhead at 86 axially and rearwardly through the tail. The shell may be constructed substantially as previously described, comprising a series of preformed sheet metal panels as shown in Fig. 2 supported by rings or hoops. Moreover, an auxiliary landing skid 59 intermediate the wheels of the landing gear may also be provided as in the previous embodiment.

In the illustrated constructions, herein shown by way of example, it will be noted that the center of gravity lies at a point near or at the neutral axis and at the forward part of the cornpartment B or B. The truss member l2 or members 90, upon which the engine may be mounted, is preferably in advance of the center of gravity, and the bulkhead formed by the members Il, Ill-I6 or by the corresponding members in the construction illustrated in Fig. 9, is in rear of the center of gravity. This bulkhead forms the focal point for substantially all forces and stresses to which any part of the plane is subjected. Substantially all stresses incident either to a level or a three-point landing are transmitted from the longitudinal trusses 9 and I8 or the trusses 80, 8l and 85, directly to the bulkhead where they are absorbed. 'I'hese stresses are not transmitted through a frame, as heretofore, from one end of the fuselage to the rear end or empennage. Moreover, substantially all forces travelling from the empennage and substantially all tail stresses are transmitted through the cantilever beam to the bulkhead where they are absorbed. Thus, longitudinal forces travelling from either end are directed into the bulkhead where they are absorbed, and torsional weight in the framing, and greater stability is secured;

I claim:

1. In an airplane, a fuselage comprising a shell and a main supporting frame, said frame comprising a continuous structural member lying substantially in a vertical plane centrally of the shell and having two sides extending longitudinally at the top and bottom of the shell and joined by two substantially vertical front and rear sides, a rearwardly extending longitudinal frame member for supporting the empennage, bracing members connecting said last named frame member to the rear portion of the main frame to provide therewith a bulkhead, the front vertical side of said main frame forming means for supporting the engine.

2. In an airplane, a fuselage comprising a continuous structural metal frame including vertically spaced longitudinally extending portions and front and rear end portions forming a compartment therebetween, a frame member secured to said frame for supporting the empennage, and an enclosing shell carried by the frame, the lower of said longitudinally extending frame portions being disposed below the shell substantially centrally of the fuselage.

3. In an airplane, a fuselage comprising a structural metal frame including vertically spaced longitudinally extending members joined at their front and rear ends to form a compartment therebetween, a frame member secured to said frame for supporting the empennage, an enclosing shell carried by the frame, the lower of said longitudinally extending members being disposed below and spaced from the shell substantially centrally of the fuselage, and a landing skid carried by said last mentioned member.

4. In an airplane structure, a fuselage body forming an enclosing shell and having an operators compartment, a main frame supporting said body, said frame having two sides extending longitudinally above and below said compartment and joined in front and rear of the compartment to substantially enclose the same, the lower of said two sides extending below and spaced from the body, and a landing skid carried thereby.

5. In an airplane structure, a fuselage body forming an enclosing shell having an operators compartment, a main frame supporting said body, said frame having two sides extending longitudinally above and below said compartment and joined in front and rear of the compartment to substantially enclose the same, the lower of said two sides exten-ding below and spaced from the body, and a wing carried thereby.

6. In an airplane, a fuselage comprising a structural frame extending substantially continuously around the operators compartment, means carried by said frame at its front for supporting an engine, a shell embracing a substantial portion of said frame, hoop shaped members mounted on the frame for supporting said shell, said shell comprising pairs of shaped panels having adjacent edges thereof hinged at one side of the fuselage, and means for connecting together the opposite adjacent edges of said panels at another side of the fuselage.

7. In an airplane, a fuselage comprising a structural frame extending substantially continuously around the operators compartment,

means carried by the front portion of said frame 8. In an airplane, a fuselage comprising astructural frame extending substantially continuously aroundl the operators compartment, a pair of landing wheels carried by said frame, the lower portion of said frame being disposed intermediate said wheels, and an auxiliary landing skid carried by said lower frame portion intermediate said wheels.

9,'In an airplane, a body including an enclosing shell having a compartment therein, a frame supporting said shell andV including a member extending below and spaced from the body intermediate its ends and designed to form a iin.

10. In an airplane, a body including an enclosing shell'having a compartment therein, a frame supporting said vshell and including a member extending below the body intermediate its ends. said member extending centrally of the body and forming a combined Iauxiliary skid and fin.

11. In an airplane, a fuselage comprising a structural frame extending around certain sides of an operators compartment, landing wheels carried by said'frame, the lower portion of said frame extending into the space between said Wheels, and a combined auxiliary landing s kid and iin carried by said lower frame portion.

12. In an airplane, a frame comprising a metallic truss structure embracing a passenger compartment, a portion of ysaid structure being spaced from and extending beneath said compartment, an empennage connected with and ex-A tending rearwardly from said truss structure,.

and a combined landing skid and fin carried by said lower truss portion.

13. In an airplane, a fuselage including as a single structural unit amidships of the plane a yoke-like frame having upright portions in front and rear of a compartment and a truss joining the same and 'extending longitudinally of the compartment, an engine ,mounting carried by the front upright portion, and a rearwardly extending cantilever tail beam for transmitting tail stresses tothe frame rearwardly of said front upright frame portion.

14. In an airplane, a fuselage including a forward upright frame structure providing an engine mounting, a tail including an empennage, an upright bulkhead spaced rearwardly of said frame structure and in advance of the tail, a longitudinal truss joining said frame s-tructure and bulkhead, the latter being disposed in reary of the center of gravity of the plane whereby landing forces are transmitted by said truss to the bulkhead and independently of the tail, and a cantilever tail beam supported from said fuselage and effective to transmit tail stresses to the bulkhead independently of said forward frame structure;

15. In an airplane, a fuselage including as a single structural unit amidships of the plane a yoke-like frame having upright portions in front and rear of a compartment and a truss joining the same and extending longitudinally of the compartment, and a rearwardly extending cantilever tail beam for transmitting tail stresses to the frame rearwardly of said front upright frame portion.

16. In an airplane, a fuselage including a forward upright frame structure, a tail including van empennage, an upright bulkhead spaced rearwardly of said frame structure and in advance of the tail, a longitudinal truss joining said frame structure and bulkhead, the latter being disposed in rear of the center of gravity of the plane whereby landing forces are transmit ed by said truss to the bulkhead and independently of the tail, and a cantilever tail beam supported from said fuselage and effective to transmit tail stresses to the bulkhead independently of said forward frame structure.

17. In an airplane, a fuselage including a con-t tinuous metal frame embracing at least three sides of a passenger compartment, said frame' extending longitudinally and centrally of the compartment and terminating at the front thereof in an upright portion and at the rear thereof in a bulkhead located amidships, and a rearwardly extending tail beam attached to said bulkhead directly in rear of the compariment and extending axially through the tail.

18. In an airplane, a fuselage.comprising a frame structure embracing a plurality of sides of a forward passenger compartment, an upright truss structure positioned rearwardly of said compartment and disposed behind the center of gravity of the plane and forming a bulkhead located amidships of the plane, a longitudinal cantilever truss joined to said bulkhead and extending through the tail, the construction being such that longitudinal stresses or forces in either direction are transmitted through said frame structure or longitudinal truss to said bulkhead and localized thereat.

19. In an airplane structure, a vertical truss arranged substantially in the vertical plane passing through the longitudinal axis of said airplane and providing the main framefor the airplane structure, said truss including a continuous member extending around the top, rear and the bottom. of the'nacelle.

' B. FIRNER. 

